Cooling system



S. W. RUSHMORE.

COOLING SYSTEM.

APPLICATION FILED MAILZI. 1921.

Patented May 17, 1921.

PATENT OFFICE.

SAMUEL W. RUSHMORE, OF PLAINFIELD, NEW JERSEY.

COOLING SYSTEM.

"Qpeciflcation of Letters Patent.

Patented May 1'7, 1921.

Continuation of application Serial No. 428,885, filed December 7, 1320. This application filed March 21,

' 1921. Serial No. 454,285.

To all wiwm it may concern:

Be it known that I, SAMUEL W. BUSH- MORE, a citizen of the United States, and resident of Plainfield, in the county of U mom and State of New Jersey, have invented certain new and useful Improvements in Cooling Systems, of which the followmg is a specification.

My present invention relates to one of the simplest and more typical formspf'the aparatus described in my p)rior application, erial No. 428,885, filed cc. 7, 1920, the form selected for this application being the internal combustion engine which has the cooling system designed and arranged so that the cooling cycle must operate by water boiling and steam condens ng.

As has long been known, coollng by the boiling and condensing cycle has great theo retical possibilities in the way of efiiclency and economy of operation of internal combustion engines, but heretofore the practical difiiculties in the wayof applying it to au-. tomobiles have proved insuperable. Although much has been said and many patents have been granted in this line, none of them seem to recognize, much less afford solution for the difficulties involved and of the hundreds of makes of automobiles and trucks now in use and on the market, there is not one wherein any attempt is made to utilize boiling and condensing for the cooling cycle. In all of them the radiator is used as a water cooler and not as a steam condenser, everything being designed so that steam evolution can never occur except by accident, and when it does occur, it requires speedy correction in order to prevent serious damage to the motor.

With ordinary water-cooling, however, it is very diflicult to design or control the system so thatthe water will always circulate at the high temperature necessary for efficiency, and many expedients have been devised with a View to cooling the water fast enough at high speeds and slow enough at ordinary speeds so as to keep the temperature approximately constant and high at all speeds, without boiling at any speed.

These expedients include thermostatically controlled valves for the water circulatlon and shutters for the air circulation, but suchproper margin of safet against boiling the 7 water, they must be a justed for temperaoperate the thermostat and open the valvef In the meantime, water in the radiator being isolated, small in quantity and very much exposed, will freeze and burst the radlator 1n a very few minutes, even when the atmosphere is at only a few degrees below freezing. The losses from this cause have been so great, that manufacturers of auto mobiles using thermostatically controlled throttles warn their customers to cut out the throttle valve and operate the cooling system in the ordinary way during freezing weather, the very time when automatic temperature control is most needed.

The difliculty of combining in one apparatus the qualities necessary to make it cool the water slowly enough for starting, slow speeds and cold weather, and yet fast enou h for high speeds, heavy loads and hot weat er, attends also the water-boiling, steam-condensing method, but the difliculties and causes of failure are different; and theyvary with the methods employed to bring aboutthe steaming and condensing.

One way which has been proposed inyolves simply draining off most of the water in the ordinary automobile cooling system so' that when the jacket is filled, the water level in the radiator is below the honeycomb. One such proposal entirely overlooks the necessity for automatic means to variably regulate the amount of water pumped back to the waterjacket, in such a way as to maintain constant level therein throughout all the wide variations in boiling rates for different engine speeds and loads. A feed pump driven by the engine at proportional speeds will not take care of the extremes of boiling rate variation; and unless there is additional automatic regulation, the water will sometimes overflow into the top of the radiator and be chilled in the usual way characteristic of water cooling, or, at other times, will boil away leaving the hottest struction, such as is commonly employed part of the water jacket empty. In general, the chillin will occur when engine heat is least, and t 1e boiling off when it is greatest,

thereby magniging temperature varlations turning the excess to the intake of the water jacket; and another by the other well known expedient of submerging the entire water circuit so that the so-called thermo-syphon circulation will be set up.

Both of these schemes, however, seem ,ito have followed the analogy of present automobile water-cooling practice, which is to discharge the cooling medium into the top of the radiator, but where steam thus replaces water as the fluid to be cooled, the radiator becomes a down-flow condenser and there results a series of unexpected difliculties. The radiator normally contains air, which is approximately 60% heavier than steam at 112 F., and when the steam comes in at the top, it traps'the heavy air below it in the honeycomb, and escape of the trapped air is then further prevented by the continuous downflow of the steam and condensate. In this situation, any overflow tube or other low resistance vent at the top. of the radiator, would let the steam escape without being condensed and without scavenging out the air. Hence a heavy safety valve must be employed to run up a high internal pressure so that the steam can push the air down far enough to expose the amount of honeycomb surface necessary for condensing the steam. The presence of the air in the condenser greatly decreases its efliciency and the high internal pressures make it dangerous to open the radlator for inspection or refilling while hot, and are otherwise highly undesirable for use on an automobile or truck. In most cases they. will make it desirable to have the ordinary standard equipment radiator replaced by heavy expensive piping and boiler-like conwherever steam is used under pressure.

On the other hand, if such down flow condensers are made of sufiicient radiating capacity to condense all the steam generated at high speeds and in hot weather, they will chill the condensate too much at other times, and in winter freezing willresult.

This is because the down-flow s stem requires the fluids to travel the ,ful distance from the top to the bottom of the condenser tubes and the less steam there is, the higher upit Wlll condense and the greater will be breathing of air from the outside into and the length of chilling tube that the condensate has to traverse.

There is a similar objection to the use of a spacious condensing chamber which is big enough and open enough to permit the steam to balloon freely to the top ofthe condensing chamber without being condensed on the way up. In such case the entire condenser is brought into play regardless of the amount of steam to be condensed, the result being that the less steam there is, the colder it Wlll get.

1 By my invention I get constant high temperatures, the lowest of which are near boiling and hence vei much higher than the highest attainable y water cooling. These temperatures I may increase up to 220 F. or 230 F. or above, by merely constricting the conduit from the water jacket to the radiator, and I may maintain approximations of these temperatures even when the boiling point of the liquid is considerably lowered as byhigh altitudes or by the addition of alcohol to prevent the water from freezing in cold weather. The latter is importa nt because in ordinary systems the alcohol lowers the boiling point to between 167- and 176 F., according to the percentage of alcohol. In my system there is practically no loss of the water, or of the alcohol, if alcohol is used. Even without alcohol the honeycomb will not freeze, as will be explained below.

So far as concerns quick warming up and maintenance of high temperatures when idling or in very cold weather, I have all the advantages derivable from the above, described by-pass or throttling expedientsfbut without the necessity of employing them.

Whatever pressures I may have in the water jacket or in the discharge conduit therefrom, there need be no pressure at all in the top of the radiator and even if I-use a slight breather valve to prevent too ready out of the top of the radiator, the slight pressures which are sustainable thereby when reat quantities of steam are being evolved, will disappear as soon as the engine is slowed down and before the operator will be able to reach and open the radiator for inspection or refilling.

Part of the above advantages are the indirect and unexpected results from the qualities which happento become available merely by selecting for my condenser, any ordinary ty e of automobile radiator. These radiators, though designed for the entirely different purpose of down-flow water-cooling and to be used in such a way that they are wholly inoperative for condensing purposes in case the water does steam, nevertheless, they happen to have the large relative arrangement of parts, and constriction of the up-and-down passages 1n the honeycomb, wlnch my experiments and,

which have been described above, can be brought about by the simple expedient of connecting the water jacket discharge plpe as well as its supply pipe, through the empty space in the bottom of such a radiator.

Referring again to the qualities of the ordinary radiator when thus connected, it will be noted that the water circulating in the bottom of the radiator cannot posslbl be adequately cooled except by boillng an as I have discovered, boiling below the honeycomb will have the effect of ejecting any surplus water at the top thereof because the up and down passages in the honeycomb are very thin, constricted say 3 inch by say 3% inches, and boilin necessarily results in a blow-off of any so id water contained in the tubes. The same thing happens where the tubes are cylindrical, because they are very numerous, small and closely set.

It will be noted also that the honeycomb is of relatively great superficial area so; that different parts of it may easily be at wldely different temperatures according to their proximities to the su ply of steam and to the action of the 6001111 fan. At the same time the thickness of the honeycomb from front to rear is short, usually about 4 inches.

Hence while different passages may be at widely different temperatures, and while the upper end of the same passage may be cold when the bottom is hot, any given cross section of a passage will have its front portion which is most directly exposed to the incom ing draft, substantially warmed by the closely adjacent rear portion.

The front of the honeycomb being somewhat cooler than the rear tends to establish a certain amount of short, rear-to-front circulation of steam, the down-flowing condensate being necessarily irrintimate heating relation with the upflowin steam so that it reaches the bottom of the oney-comb at steaming temperature.

The aggregate cross sectional area of all the passages for upflow of steam in the honeycomb is small as compared with the height, and though varying somewhat with the make and power of the automobile, it is,

for instance, something like 7 square inches for a 6 cylinder 25 horse power en ine, while the amount of steam that must nd escape through this area, split up, as it is, into such a multiplicity of passages, is always great enough to maintain a swift steady flow of the steam pressing straight on upward while being continuousl diminished by condensation, until it is al condensed. ence it results that the steam sweeps the air upward out of all the active parts of the honeycomb and toward the low resistance outlet at the top; while, on the other hand, the steam cannot deposit water except in said active parts of the honeycomb whence the entire path of down-flow of condensate is through said active parts which are being kept at boiling point by the continuous upfiow of steam.

Increased volume of steam due to increase of load upon the motor, or decreased cooling efficiency of the air, as in hot weather, may result in raising or lowerin the height of the circulation, but without c ianging the intimacy between the upfiow of steam and the downflow of condensate.

The front-to-rear thinness of the honeycomb, its small base area for entry of steam as compared with its height, and the multi-- plicity, smallness, and close setting of tubes or passages, all contribute to make definite and dependable the above described automatic increase and decrease of the height of the'circulation in the honeycomb and the exact automatic regulation of the actively operating condenser area, so that the condensate is returned at boiling temperature regardless of how little or how much steam is being generated.

The honeycomb will not freeze up when connected and operated in accordance with my invention. This is because the honeycomb is normally dry; it is wetted onl 1 by condensed steam penetrating upward rom below; the passages are so constructed that they will not be wet any higher up than the points that are kept warm by steam condensation and of course not as high as the further points that are kept above freezing by conduction in the metal walls; wetted areas are constantly drained by gravity; and as soon as the steam recedes they are dried by the heat reabsorbed from the adjacent metal. Since the wetted area recedes downward when the steam recedes, there will be no water to freeze in the parts of the radiator an automobile running ten miles to the gallon of gasolene, or say four gallons per 'hour, at 40 miles per hour, requires only six or eight gallons of water per hour to be boiled and recondense'd. A much greater supply of water, however, can do no harm, because it enters the jacket hot, that is near 212. Hence, while my system may be specially designed for circulating only a twenty gallons of water per hour, thereby safe margin of surplus water, say ten to jacket spaces in the motor are so formed that high speed circulation of excess water is necessary to keep them swept clear of steam and trapped air. It is therefore an advantage of my system that its success does not depend on limiting the speed of circulation of the water.

In my earlier experiments, which have since resulted in successfully applying my above method to standard automobile equipment, I encountered two difficulties. The first is that although my present method requires circulation of only a small amount of water, this water when changed to steam increases in volume over seventeen hundred times with the result that friction in the return conduit from the water jacket to the radiator may be considerable and may cause back pressure on the water jacket. I have discovered, however, that when desired, this canbe gotten rid of by using a sufficiently large conduit at this point. Preferably, however, it is turned to advantage by using a constricted conduit, and

- varying the constriction to get any desired back pressure on the water jacket. This expedient makes it easily possible to raise the boiling point in the water jacket to 220 F. or 230 F., or above, where water alone is used, and it is'of particular advantagewhere alcohol and water mixtures are used, because thereby the boiling point of the mixture, which may be say 167 to 176 F., can be raised to the desired extent. This necessitates the use of a positively acting pump, the pressure on the up-side of the water circuit being abnormally increased by.the back pressure of steam in the discharge. Furthermore, the water drawn from the bottom of the radiator being at boiling point must go to the intake of the pump by gravity, because applying suction to draw it up will only result in permitting evolution of steam to satisfy the suction, without lifting the water.

For .all of these reasons, the intake of the pump should be at or below the normal level of water in the radiator, and the pump should be a force pump adapted to positively force the water into the water jacket against gravity, and against any back pressure of steam that can exist even under the worst conditions.

It will be noted that while the honeycomb as a whole is in one sense in shunt relation to the low resistance path of the water through the bottom of the radiator, it lalso has the relation of a vent or open honeycomb below which force-feed circuit 2-2, Fig. 1, in which the construction is pumpl 9, the latter being preferably driven conduit in series between the steaming section'of the circulation and the outer atmos phere, but of. such a nature that in normal operation the steam cannot get out because it is condensed before it gets far enough. Hence it operates in effect like a massless, pressureless safety valve to prevent all escape of steam to the atmosphere except under very abnormal conditions when it is highly desirable that such escape be permitted.

The above and other features of my forcefeed circuit for'water and steam, combined with the variable height circulation in a releases steam, ma all be more fully understood from the ollowing description and the accompanying drawings, in which Figure 1 is a side elevation conventionally indicating the usual elements of a, water cooling system as commonly employed on automobiles, etc., but arranged so as to embody one form of my invention;

Fig. 2 is a vertical section on the line diagrammatically indicated;

- Fig. 3 is a similar view on the line 3-3,' Fig. 2;

Fig. 4 is a true size detail section on the line 4-4, Fig. 2; '95 Fig. 5 is a detail showing another illustrative form of air cooled radiator which may be employed Fig. 6 is a vent. Fig. 1 shows the usual crank case 1 and cylinder block 2 of a four cylinder motor of the automobile type, the upper parts of which are inclosed by water jacket 3. The water cooling system is conventionall indicated as including the radiator 4 pre erably located on the same level with the motor and directly infront of it, so that the lower part of the radiator is below the level of the water-jacket of the motor. The circulation of the water from the bottom of the radiator, is through a conduit comprising outlet 5, flexible coupling 6, and pipe 8 to' detail'section showing a valved by t e engine at directly proportioned 1 speeds. The pump is indicated as being a gear pump but this is only to illustrate the pump which may be of any known or desired construction, adapted to receive boiling water and force it into and through the water jacket against friction and any back pressure that may be caused by steaming. The pump discharges through a conduit including pipe 10, branches. 15, 16, water jackets 3, outlet pipe 17, 18 and a single return pipe 19. The pipe 10 may contain a check valve 7 toinsure against back flow of water or steam, as might otherwise happen under certain conditions, as for instance, when the engine and pump stop. 130

direction of the exit through pipe 5, but,

this is not necessary. 7

The important point is to afford the incoming hot water a relatively low resistance, low pressure path in the bottom of the radiator, to the outlet 5. All of the desirable relations may be attained by arranging the discharge path through the usual horizontal cavity, beneath the honeycomb section which is the main, effective radiating element of the structure. Thus arranged the bottom of the radiator constitutes an effective steam separator operating to facilitate evolution and escape of steam from the in coming hot water.

The honeycomb is conventionally indicated as comprising thin sheet metal walls affording fore and aft passages a, a for the air draft which are usually about 4 inches through, by about inch diameter; also interior vertical passages b, b for vertical circulation of the hot fluid in intimate contact with the large air radiating surfaces constituting the air passages. In the type here indicated these vertical passages are usually about 3 2 inch by 3% inches to 4 inches in horizontal cross section and the number of them may be suflicient to afl:'ord an aggre ate flow section of about 7 square inches. 11 other types of honeycomb there are cross passages as at 0, 0 Fig. 5, affording opportunity for cross circulation. In this form the vertical passages are not straight, but the cross tubes are so many, so small, and so closely set that thefunctioning is not materially different so far as concerns the de sirable features heretofore described as attainable by the use of any of these well known types of automobile radiators.

Where the honeycomb is of the type comprising a multiplicity of upright cylindrical tubes held in cross-members that serve as cooling ribs or fins, the desired limitedheight, up-and-down flow in individual tubes will occur, though the tubes be not more than 2; inch in diameter.

With any of these arrangements, it is ob-- vious that while the water is cool it will be pumped around and around through the circulating system and across from inlet nozzle 26 through the low resistance path to outlet pipe 5, until the incoming water begins to liberate steam, which will rise and set up the circulation in the honeycomb.

Even if the radiator has been filled to or above the honeycomb, it is not likely to remain full ver long because I prefer to employ an overfi ow pipe 20, or othersuitable connection with the outer air, whereby the interior of the radiator. is kept at or near atmospheric pressure. Hence the incoming watei. will become actively boiling, and the conditions are such that this operates to force any surplus water or air upward and out through the overflow pipe 20.

The water in the radiator being at or be-. low the bottom of the honeycomb, either by original filling or by automatic ejection of surplus, if over filled, the functioning of the device at the various speeds from idling speeds or cold weather conditions and through the intermediate variations up to and including the highest speeds and heaviest loads in the hottest weather, will be, ac cording to the methods heretofore described. In the drawings the pump is shown as having its intake at, or below the lowest level of the water in the bottom of the radiator so that under normal conditions when the water is at boiling point and will not respond to suction, the intake will be supplied by gravity flow. The showing of the pump is indicated as diagrammatic, but it will be understood that it must be sufficiently positive so that at low speeds and under allconditions it will be able to force the required amount of water through the water jacket against friction and any back pressure that may be set up by steam evolution. I

The back pressure on the water jacket will depend on the size of the pipe leading from the top of the water jacket to the bottom of the radiator, or, more strictly speaking, upon the total resistance which this conduit offers to the passage of the steam. A throttle valve to vary the constriction of this conduit may be of advantage, particularly for aeroplanes, since a proper constriction will keep up the boiling point in the water jacket independently of the altitude of flight. Such throttle may have automatic control, either pressure or thermostatic, without danger of freezing the radiator.

While the specific purpose which I have had in view has been the embodiment of above steam cooling methods, in the present day constructions of automobiles, trucks and the like without materially changing the structure of the radiators which are designed for down flow of the hot water, nor

their proportions, nor their location in front of the engine with the lower collecting cavity considerably below the level of the water jacket, and while there is special advantage in my discovery that now standard apparatus can be utilized for my purpose with only slight changes involving no additional parts and practically no expense, it will be evident that in any new apparatus especially adapted for the practice of m invention, various changes. may be ma e; also that various features contributing'to the success of my invention may be em loyed either together or separately for ana ogous purposes, in other apparatus, as for 1nstance in airplanes, and stationary plants.

For instance, the vent to atmosphere at the top of the radiator may have its resistance very substantially increased by a safety valve, thereby increasing its condensing caacity, without endangering any of the well built radiators of standard types; and by employing special constructions, the pressure may be raised to any desired extent; and of course heavier more substantial constructions may be specially desired.

While the space in the bottom of an ordinary radiator will hold all the Water really needed, a greater supply may be provided for by laterally enlarging the radlator at this point, and obviously the filler cap may be located much lower down, near the normal level of the water.

In the form shown in the drawings there is a small cock located at approximately the desired water level, through which the water may be drawn down to said level. This should of course be done while the pipes and water jacket are kept full by running 'of the motor.

As the capacity of the ordinary honeycomb is more than sufficient-to condense all the steam that can be formed'in the operation of the engine for which the radiator is designed, it is quite possible to cheapen construction by decreasing the size of the'honeycomb, in which case the space saved may be utilized for containing a larger supply of water.

The term honeycomb herein is used in a rather broad sense toindicate the main active heat-dissipating elements of the radiator, the important features of which, so far as concerns my present invention, are the upflow paths'for the steam adapted for down drainage of water; the small aggre gate flow-section of the paths as compared with their height; and the open tops for the paths whereby air forced up from below by the steam may escape into a common cavity or to the open air.

These and other features: whereby the flow of steam is steadily and rapidly upward even when the steam production is smallest, and whereby variations in the amounts of steam are taken care of merely by varying the height to which the steam penetrates,

nary filler cap, to serve as the low resistance of t e condenser will be greatly. increase If desired, a similar but op ositely directed valve 30 may control in ct passages .32, whereby air ma be admitted and vacuum prevented or relieved. These valves may be protected by closure cap 27 having normally open vents 28. v

I claim: g 1. In a motor vehicle of the general type characterized by an internal combustion engine of widely variable speed and heating .75 lbs. Iper square inch, the maximum capacity capacity and water-j acketed for cooling purposes; an air cooled radiator located in front of one end of the motor, comprising an intermediate ortion of great heat radiating capacity a ording a multiplicity of transverse paths for through flow of the cooling air, and interior, up-and-down paths for upflow of steam and drainage of water b gravity, a lower ortion of small heat radiating capacity a ording a collecting cavity into which said paths drain and'in which the water level is maintained below the level in the water jacket, and an upper cavity to which all s'ald paths are open for escape of air; and a conduit with force pumping means leading from the lower collecting space in the radiator tothe water jacket; and, in combination with the said elements of such a vehicle, means for operating said pumping means at a rate sufficient to oversupply the water-jacket, and a single continuous return conduit for the surplus water and steam leading from the upper part of the water jacket discharging into said lower collecting space in the radiator, thereby causing separation of the surplus water and steam in the lower part of the radiator and continuous flow of steam upward into .said upward paths, forcing air or other excess fluids above it into the upper cavity in the radiator.

2. In a system for cooling an internal combustion engine by the boiling and condensing cycle, an internal combustion engine jacketed for application of the cooling liquid, a radiator comprising a condenser portion of large radiating capacity having a flow path which is of small flow section as compared with its length and which is open at both ends for in and out flow of fluids, a container of low radiating capacity closing in one end only of said flow path and into wh ch the latte dr i s, in; c m n ion with a force pump and circuit for forcing fluid serially through the jacket and said container at rates suflicient to over-supply the water jacket, and connecting with said con- 5 denser only through said container the parts being proportioned and arranged to maintain the level of the liquid in the container below the level of the adjacent end of the flow path through the condenser.

3. A cooling system for Water-jacketed internal combustion engines, said system comprising in part, a force pump circuit for continuously clrculating an over-supply of cooling fluid which is of small radiating 5 capacity; and in part, upwardly extending tubes each open at the upper. as well as the lowerend and constituting a condenser of great radiating capacity, and which is v cated above an exposed portion of said circuit wherein the steam is separated from the surplus circulating water and whereby steam separated from the water can flow directly into the lower-ends of said tubes; the air forced out by the rising steam can escape from the upper ends of the tubes; and the water of condensation can flow by gravity directly from the same tubes.to the water circulating system. Y

4. In a cooling system for internal com bustion engines, a force feed water circulating system of small heat'radiating capacity serially including a water jacket, awater outlet pipe from said jacket, and a water container to which said pipe is connected, in

3 combination with large capacity radiating means above the water container, interposed between it and a low resistance outlet for escape tothe outer air for steam, air or water.

5. In a cooling system for internal com- 40 bustion'engines, a force feed water circulating system of small heat radlating capacity serially including" a water jacket, a water outlet pipe from said jacket, and a water container to which said pipe is connected,

in combination with large capacity radiating means above the water container, interosed between it and a low resistance outlet or escape to the outer air for steam, air or water, the flow section for the steam being relatively small as compared with the total condensing capacity so that the steam will penetrate thecondenser only to a distance proportional to the'amount of the steam.

6. In a system for cooling an internal combustion engine by the boiling and condensing method, an internal combustion en-- gine jacketed for application of the cooling liquid, a radiator comprising a condenser portion of condensing capacity equal to the 0 maximum requirements of the engine but of relatively small flow section for the purpose described and a water container communicating with one end only of the flow path and into which the latter drains, in combination with a force pump circuit through the jacket and said container of small radiating capacity operating to over-supply the water jacket and to maintain the level of the liquid in the container below the level of the adja-- cent end of the fiow path through'the condenser. t

7-, In a system for cooling an internal combustion engine by a boiling and condensing cycle, an internal combustion engine jacketed for the application of the cooling liquid, a radiator comprising a condensing portion having a fiow path which is: of small cross-section as compared with its length, and which is open at both ends for in and out flow of liquids, a container adapted to serve as a steam separator communicat ing with one end only of said flow path and into which the latter drains, in combination with a force pump and circuit for forcing all the circulating fluids serially through the engine jacket and said container at rates sufiicient to over-supply isaid jacket; the part of said circuit which leads from the water jacket to the container being constricted to afford desired resistance and resultinIg back pressure in the water jacket.

8; n a system for cooling an internal combustion engine by the boiling and condensing method, an internal combustion engine jacketed for application of the cooling liquid, a radiator comprising a-con'denser portion of condensing capacity equal to the maximum requirements of the engine but of relatively small flow section for the purpose described, and a water container ofrelatively small radiating capacitycommunicating with one end only of the flow path and into which container the flow path drains, in combination with a force pump and circuit for forcing water serially from the -container through the acket and theresulting water and steam into said container, at rates suliicient to over-supply the water'jacket; the parts being proportioned and arranged to maintain the level of the liquid in the container below the level in the water jacket.

9. In a2 system for cooling an internal combustion engine by the boiling. and condensing cycle, an internal combustion engine jacketed for application of the cooling liquid, a radiator comprising a condenser portion of lar e radiating capacity having a fiow path wliich is of small flow section as compared with its length and which is open at both ends for in and out flow of liquids, a container of small radiating capacity communicating with one end only of said flow path and into which the latter drains, in combination with a force pump and circuit for forcing water serially from the container through the jacket and the resulting water and steam into said container, at rates sufficient to over-supply the water jacket; the parts being proportioned and arranged to maintain the level of the liquid 130 in the container below the level in the water jacket.

10. In a motor vehicle of the general type characterized by an internal rombustion engine of widely variable speed and heating capacity and water-jacketed for cooling purposes; an air cooled radiator comprising an intermediate portion of reat heat radiating capacity, relatively tiin from front to rear, affording a multiplicity of transverse paths for through flow of cooling air, and interior, up and down paths of small flow section for upflow of steam and return drainage of water by gravity, a lower portion heat radiating capacity much less than the average heat generating capacity of the en ine, affording a collecting cavity into whic said paths drain and in which the water level is lowered below the level in the water jacket, and said radiator having also an uppercavity to which all said paths are open for esca e of air; and, in combination with said e ements of such a conduit having its intake supplied by gravity from said col cting s ace, adapted to fully supply the water ac et with water at all speeds and when the water is boiling regardless of the variations of heat and back pressure in the water jacket; a return conduit from the upper (part of the water jacket discharging into sai lower collecting space in the rad1ator; thereby facilitatin evolution of steam and discharge thereo in the lower part of the radiator and continuous flow of steam upward into said upward paths, forcmg air or other excess fluids above it into the upper cavity in the radiator.

Signed at New York, in the county of New York, and State of New York, this 19th day of March, A. D. 1921.

I SAMUEL W. RUSHMORE. 

